In a large number of production runs, machining operations are performed automatically, with specific fixtures being used for the machining and handling of the workpieces, in order to achieve maximum efficiency and productivity.
In particular, for each workpiece often there are several successive machining steps, which are conveniently performed in an automatic line, wherein the workpieces are automatically transferred via transporters or the like from one machine to the other. The machines can be conveniently equipped with automatic manipulators (robots) for removing the workpiece from the transporting line, effecting their transfer to the machine and subsequently returning them to the transfer line.
For this purpose, it is generally necessary that the workpieces to be machined be arranged in an orderly manner in a support fixture of the transport line, consisting of cassettes or pallets, with shapes adjusted to receive and maintain the workpieces in a well-determined position, particularly in the cases where the workpieces have to be handled by automatic manipulators or robots.
In such cases, it is desirable to provide support fixtures which negatively reproduce the contours of the workpiece to be received. It is necessary to have a number of such pallets equal to the number of positions in a magazine, in the case of magazine-fed machines, and in the case of line transporters, as many pallets as there are successive positions on the line.
In any case, the number of such support fixtures for workpieces which a machinery line may require is quite high, and can vary between tens of pieces to several hundred.
In the case when on the same machine or system, workpieces of various shapes have to be machined, it is necessary to provide a complete series of support fixtures for each type of workpiece to be machined, with high production costs and considerable time and effort for the replacement of the support fixtures, every time the type of workpiece is changed.
This of course creates an impediment to automation, making it preferable in many cases to have an operator who can manually transfer the pieces to the operating machine, instead of deploying an automatic manipulator, which requires a large number of support fixtures.